Minimum Number of Days to Disconnect Island LeetCode solution in JavaScript

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let directions = [
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  [-1, 0],
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  [1, 0],
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  [0, -1],
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  [0, 1],
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];
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var minDays = function (grid) {
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  let colorNumber = 2;
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  let landCells = [];
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  function colorIsland(i, j) {
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    grid[i][j] = colorNumber;
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    for (let k = 0; k < directions.length; k++) {
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      let newI = i + directions[k][0];
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      let newJ = j + directions[k][1];
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      if (
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        newI >= 0 &&
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        newJ >= 0 &&
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        newI < grid.length &&
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        newJ < grid[0].length &&
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        grid[newI][newJ] &&
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        grid[newI][newJ] != colorNumber
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      ) {
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        colorIsland(newI, newJ);
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      }
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    }
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  }
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  function addLandCells() {
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    for (let i = 0; i < grid.length; i++) {
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      for (let j = 0; j < grid[0].length; j++) {
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        if (grid[i][j]) {
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          landCells.push([i, j]);
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        }
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      }
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    }
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  }
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  function findAnotherIsland() {
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    for (let i = 0; i < grid.length; i++) {
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      for (let j = 0; j < grid[0].length; j++) {
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        if (grid[i][j] && grid[i][j] != colorNumber) {
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          return true;
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        }
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      }
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    }
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    return false;
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  }
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  addLandCells();
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  if (landCells.length < 2) {
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    return landCells.length;
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  }
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  colorIsland(landCells[0][0], landCells[0][1]);
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  if (findAnotherIsland()) {
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    return 0;
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  }
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  colorNumber++;
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  for (let i = 0; i < landCells.length; i++) {
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    grid[landCells[i][0]][landCells[i][1]] = 0;
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    colorIsland(
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      landCells[(i + 1) % landCells.length][0],
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      landCells[(i + 1) % landCells.length][1]
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    );
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    if (findAnotherIsland()) {
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      return 1;
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    }
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    grid[landCells[i][0]][landCells[i][1]] = colorNumber;
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    colorNumber++;
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  }
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  return 2;
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};